1. Field of Invention
The present invention relates to a timing controller for a liquid crystal panel and a timing control method thereof, and more particularly to a timing controller for a liquid crystal panel and a timing control method thereof capable of automatically detecting a frequency of a system signal to switch to output a trigger signal corresponding to a frame rate, and at the same time controlling an output time of the trigger signal.
2. Related Art
FIG. 1A is a schematic view of a circuit architecture of a liquid crystal panel in the prior art. Currently, a gate in panel (GIP) technology has been widely used in manufacturing technologies of liquid crystal panels, which can decrease the fabrication cost of the liquid crystal panel, as no additional gate driver integrated circuit (IC) needs to be used when a shift register circuit 13 of a gate drive circuit is directly implemented in the panel (dashed line block in FIG. 1A). However, the circuit design manner of a source driver IC 15 is not changed.
FIG. 1B and FIG. 1C are timing diagrams of different working trigger signals for a circuit architecture of a liquid crystal panel in the prior art, and reference is made to FIG. 1A at the same time for ease of understanding. In an existing power saving mechanism of the liquid crystal panel, generally when a sleep mechanism is enabled, a frame rate of a working trigger signal is decreased to reduce an operational efficiency of hardware, so as to further achieve the objective of power saving. When a working mechanism is enabled, the frame rate of the working trigger signal is restored.
As shown in FIG. 1B, in a working mechanism period, a timing controller 11 supplies a working trigger signal having a frame rate of 60 Hz to a level shift circuit 12, and a charge time of each liquid crystal unit is between a falling edge of the trigger signal (TP) and a falling edge of a clock signal line (clk1˜4) corresponding to the TP.
Further in FIG. 1C, in a sleep mechanism period, the timing controller 11 supplies a working trigger signal having a frame rate of 40 Hz, and the charge time of each liquid crystal unit is longer than that in the environment with the frame rate of 60 Hz. Therefore, when the frame rate is switched, a situation of inconsistent charge time might occur to the liquid crystal units, which leads to different display intensities of the liquid crystal panel, further resulting in a situation of instant flickering pictures.
However, the liquid crystal panel having the GIP architecture does not have Out Enable (OE) signal control lines. Therefore, the liquid crystal panel cannot use the OE signal control lines to adjust an enable time of a semiconductor channel layer of a thin-film transistor (TFT) element for a charge time of a liquid crystal unit connected to a gate line 14 of the shift register circuit 13, so as to control the charge time of the liquid crystal unit.
Therefore, the manufacturers shall consider the problem of how to avoid flickering pictures when the liquid crystal panel switches the frame rate.